|When XP boots it starts the automatic user logon process (explorer.exe) before finishing loading the network. This creates a "race condition" when the logon process is trying to draw the taskbar icons while the system process is still initializing networking (and its icons, especially wi-fi.) Meanwhile, drawing of "less important" icons times out before networking is done and that's how you get missing icons.|
You will remember that this problem did not exist in Win2k. That's because Win2k loaded its networking stack before starting the user logon. There is a way to revert XP to Win2k-like behavior:
1. Open Run dialog (Windows+R) & type gpedit.msc, press Enter. Group Policy Editor starts.
2. In the left pane navigate to Computer Configuration - Administrative Templates - System - Logon.
3. In the right pane find "Always wait for the network at computer startup and logon". Double-click and select Enabled, hit OK, close GPE.
4. Reboot. Now XP will boot-up Win2k-style: first all the system stuff, then the user logon.
P.S. Group Policy Editor is a nifty hidden program that can change a lot of other cool settings, like Autoplay/Autorun for example. Have a look around and read the descriptions.